POSITIVE AND NEGATIVE VOLTAGE GENERATING CIRCUIT, LIQUID CRYSTAL DISPLAY MODULE DRIVING SYSTEM, AND VOICE OVER INTERNET PROTOCOL PHONE

摘要

A positive and negative voltage generating circuit includes a first rectification circuit, a first voltage stabilizing circuit, a boost circuit, a second rectification circuit, and a second voltage stabilizing circuit. The first rectification circuit rectifies input voltage signals. The first voltage stabilizing circuit stabilizes the rectified input voltage signals to output a negative voltage needed by an LCD module. The boost circuit up-converts the input voltage signals to output a first voltage. The second rectification circuit rectifies the first voltage. The second voltage stabilizing circuit stabilizes the rectified first voltage to output a positive voltage needed by the LCD module. An LCD module driving system and a VOIP phone are also provided.